The invention refers to a bicycle frame comprising a main frame consisting of a seat tube, a down tube and a top tube, a rear structure with a couple of chain crossbars and a pair of saddle crossbars that are connected with their rear ends each with an end run for linkage to the rear axles, whereby the chain crossbars are each linked at their front ends with a first fixed linkage point of the main frame as well as a see saw equipped with three see saw linkage points. The first see saw linkage point is connected to the front end seat crossbar and the second see saw linkage point is linked pivotally to a second fixed linkage point of the main frame while a third linkage point is connected pivotally to the first end of a spring cushioning element.
Such a bicycle frame is known, for example from EP 0 912 391 B1. However, a second end of the spring cushioning element has a fixed connection with the main frame.
Such frame constructions are called in practice multiple joint frames or four-joint frames. In principle, the rear structure is connected via the front ends of the chain crossbars with a first fixed support in the area of the pedal bearing and via the front ends of the saddle bars with a seesaw mounted on the main frame, preferably on the seat tube that is connected with its first end of the spring cushioning element and whose second end is mounted to the main frame in known designs.
The known frame systems show a very direct responding behavior of the springs during pedaling lading to an especially undesired seesawing of the rear structures.
Therefore, it is the challenge of the present invention to further develop a bicycle frame of the above mentioned type to achieve a delayed responding behavior of the suspension and to at least severely limit undesired seesawing of the rear structure during pedaling.